httpd is vulnerable to side-channel attack. An implementation flaw was discovered in multiple cryptographic libraries that allows a side-channel based attacker to recover ECDSA or DSA private keys. When these cryptographic libraries use the private key to create a signature, such as for a TLS or SSH connection, they inadvertently leak information through memory caches. An unprivileged attacker running on the same machine can collect the information from a few thousand signatures and recover the value of the private key.
www.securitytracker.com/id/1041144
www.securitytracker.com/id/1041147
access.redhat.com/errata/RHSA-2018:3221
access.redhat.com/errata/RHSA-2018:3505
access.redhat.com/errata/RHSA-2019:1296
access.redhat.com/errata/RHSA-2019:1297
access.redhat.com/errata/RHSA-2019:1543
access.redhat.com/errata/RHSA-2019:2237
access.redhat.com/security/updates/classification/#important
dev.gnupg.org/T4011
git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=9010d1576e278a4274ad3f4aa15776c28f6ba965
issues.jboss.org/browse/JBCS-620
lists.debian.org/debian-lts-announce/2018/06/msg00013.html
lists.gnupg.org/pipermail/gnupg-announce/2018q2/000426.html
usn.ubuntu.com/3689-1/
usn.ubuntu.com/3689-2/
usn.ubuntu.com/3692-1/
usn.ubuntu.com/3692-2/
usn.ubuntu.com/3850-1/
usn.ubuntu.com/3850-2/
www.debian.org/security/2018/dsa-4231
www.nccgroup.trust/us/our-research/technical-advisory-return-of-the-hidden-number-problem/
www.oracle.com/technetwork/security-advisory/cpuapr2019-5072813.html